How to create a seamles UV map for an hexagonal grid texture?
I haven't played RL in a while, but are the ceilings the same beveled rectangle shape?

It looks like your images are being stretched as they get closer to the beveled edge.  It also looks like your screenshot isn't from Blender, so I don't know how to do it in whatever software that is, but if you're working in Blender I'd suggest going to UV mode and adjusting the vertices until it looks better.  Also, check your texture and see how the edges line up at the top/bottom and left/right.  It might take some photo editing and/or scaling to get it to work.

Good luck!